/*
 * Copyright (C) 2008 Pleyo.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Pleyo nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY PLEYO AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL PLEYO OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef PlatformWheelEvent_h
#define PlatformWheelEvent_h

#include "IntPoint.h"
#include "BALBase.h"


namespace WebCore {

    // Wheel events come in three flavors:
    // The ScrollByPixelWheelEvent is a fine-grained event that specifies the precise number of pixels to scroll.  It is sent by MacBook touchpads on OS X.
    // For ScrollByPixelWheelEvents, the delta values contain the precise number of pixels to scroll.
    // The ScrollByLineWheelEvent (the normal wheel event) sends a delta that can be corrected by a line multiplier to determine how many lines to scroll.
    //      If the platform has configurable line sensitivity (Windows), then the number of lines to scroll is used in order to behave like the platform.
    //      If the platform does not have configurable line sensitivity, then WebCore's default behavior is used (which scrolls 3 * the wheel line delta).
    // For ScrollByLineWheelEvents, the delta values represent the number of lines to scroll.
    // The ScrollByPageWheelEvent indicates that the wheel event should scroll an entire page instead.  In this case WebCore's built in paging behavior is used to page
    // up and down (you get the same behavior as if the user was clicking in a scrollbar track to page up or page down).  Page scrolling only works in the vertical direction.
    enum PlatformWheelEventGranularity { ScrollByLineWheelEvent, ScrollByPageWheelEvent, ScrollByPixelWheelEvent };

    // WebCore uses a line multiple of ~3 (40px per line step) when doing arrowing with a scrollbar or line stepping via the arrow keys.  The delta for wheeling is expressed
    // as a # of actual lines (40 / 3 = 1 wheel line).  We use the horizontalLineMultiplier and verticalLineMultiplier methods to incorporate the line multiplier into the deltas.  On
    // platforms that do not support wheel sensitivity, we use this hardcoded constant value of 3 to ensure that wheeling by default matches the WebCore multiplier you
    // get when doing other kinds of line stepping.
    const int cLineMultiplier = 3;

    class PlatformWheelEvent {
    public:
        const IntPoint& pos() const { return m_position; } // PlatformWindow coordinates.
        const IntPoint& globalPos() const { return m_globalPosition; } // Screen coordinates.

        float deltaX() const { return m_deltaX; }
        float deltaY() const { return m_deltaY; }

        PlatformWheelEventGranularity granularity() const { return m_granularity; }

        bool isAccepted() const { return m_isAccepted; }
        bool shiftKey() const { return m_shiftKey; }
        bool ctrlKey() const { return m_ctrlKey; }
        bool altKey() const { return m_altKey; }
        bool metaKey() const { return m_metaKey; }

        int x() const { return m_position.x(); } // PlatformWindow coordinates.
        int y() const { return m_position.y(); }
        int globalX() const { return m_globalPosition.x(); } // Screen coordinates.
        int globalY() const { return m_globalPosition.y(); }

        void accept() { m_isAccepted = true; }
        void ignore() { m_isAccepted = false; }
        
        PlatformWheelEvent(BalEventScroll*);

    private:
        int horizontalLineMultiplier() const { return cLineMultiplier; }
        int verticalLineMultiplier() const { return cLineMultiplier; }

        IntPoint m_position;
        IntPoint m_globalPosition;
        float m_deltaX;
        float m_deltaY;
        PlatformWheelEventGranularity m_granularity;
        bool m_isAccepted;
        bool m_shiftKey;
        bool m_ctrlKey;
        bool m_altKey;
        bool m_metaKey;

    };

} // namespace WebCore

#endif // PlatformWheelEvent_h
